Field of the Invention
The present techniques relate to a method for producing a Group III nitride semiconductor light-emitting device. More particularly, the techniques relate to a method for producing a Group III nitride semiconductor light-emitting device, which can provide a p-type cladding layer having high crystallinity.
Background Art
Group III nitride semiconductor crystals are produced through vapor phase growth techniques such as metal organic chemical vapor deposition (MOCVD) or hydride vapor phase epitaxy (HVPE); molecular-beam epitaxy (MBE); pulsed sputter deposition (PSD); liquid phase epitaxy (LPE); or a similar technique.
Among these techniques, when semiconductor layers are grown by MOCVD, various gases are fed to an MOCVD furnace, and the semiconductor layer is formed in the atmosphere of the furnace. Patent Document 1 discloses a technique for growth of a semiconductor layer, wherein
a nitrogen gas atmosphere and a nitrogen-hydrogen gas mixture atmosphere are selectively employed, depending on the composition of the semiconductor layer to be formed. (see Patent Document 1, paragraph [0107]).
Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. 2013-175790
Meanwhile, polarity inversion defects may be generated in a Group III nitride semiconductor layer during growth thereof. A polarity inversion defect refers to a defect caused by intermingling of an N-plane with a Ga-plane. The number of polarity inversion defects per unit area of a plane orthogonal to the direction of growth of the semiconductor layer is defined as “polarity inversion defect density.” The lower the polarity inversion defect density, the higher the crystallinity of the semiconductor layer.
Generally, the polarity inversion defect density increases with the progress of epitaxial growth. In other words, the polarity inversion defect density at the later stage of epitaxial growth is generally higher than that at the initial stage of epitaxial growth. Thus, suppression of an increase in polarity inversion defect density in the course of epitaxial growth is preferable.
In a growth atmosphere containing hydrogen gas, some semiconductor layers may be damaged during growth thereof. Thus, it is preferred that an increase in polarity inversion defect density is suppressed, without degradation of the crystallinity of the semiconductor layer during growth.